Range and distribution of mental abilities in a group of high-grade mental defectives

Abstract

This study is based on 38 mental defectives above 16 years with IQ's between 50 and 70. An analysis of 34 pencil and paper and performance tests covering various abilities reveals that on the average the range in ability is 80% as great as the individual differences. This finding is in agreement with that of Hull for normal subjects. (PsycInfo Database Record (c) 2025 APA, all rights reserved)